<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>盒子模型</title>

    <style>
        div {
            border: 1px solid blue;
            width: 100px;
        }

        .div1 {
            width: 100px;
            height: 100px;
            /* 外边距 */
<!--            margin: 50px;-->
        }

        .div2 {
            width: 200px;
            height: 200px;
            /* 内边距 */
            padding: 50px;
            box-sizing: border-box;
        }

        .div3 {
            float: left;
        }

        .div4 {
            float: left;
        }

        .div5 {
            float: right;
        }
    </style>

</head>
<body>

<div class="div2">
    <div class="div1"></div>
</div>

<div class="div3">aaaa</div>
<div class="div4">bbbb</div>
<div class="div5">cccc</div>

</body>
</html>